The present invention relates to a heat exchanger such as a laminate evaporator for an air conditioning system of a motor vehicle or the like.
The type of heat exchanger to which the present invention constitutes a novel and advantageous improvement comprises a plurality of generally flat, hollow panels which are stacked together with corrugated plates or the like interspersed therebetween, and end plates applied to both ends of the stacked panel and corrugated plate assembly.
Where the heat exchanger is used an an evaporator, a refrigerant fed into the bores flows through the hollow panels along a zig-zag path and passes out of the evaporator. Air to be cooled is pumped through the corrugated plates. The refrigerant flowing through the panels absorbs heat from the air, thereby lowering the temperature thereof.
An inlet conduit extends outs from a refrigerant inlet which is formed through one of the opposite end plates and has an expansion valve therewith, while an outlet conduit extends out from an refrigerant outlet which then is inevitably formed through the other end plate to provide the zig-zag refrigerant path. Such a relative position of the inlet and outlet, however, gives rises to some problems. Since a temperature-sensing bulb and an external equalizer responsive respectively to the temperature and pressure in the outlet conduit are incorporated in the expansion valve of the prior art heat exchanger, it is necessary to position the expansion valve near the outlet conduit traversing the front face of the heat exchanger. The expansion valve located in front of the heat exchanger constitutes resistance to the flow of air which is detrimental to the performance of the heat exchanger. In addition, the cost of the prior art heat exchanger is disproportionate due to the provision of the expansion valve, temperature-sensing bulb and external equalizer which are separate from each other and intercommunicated by tubings.